Pushing to the hub

slides/intro/Publishing_To_Docker_Hub.md

@@ -2,19 +2,72 @@
 
 We have built our first images.
 
-If we were so inclined, we could share those images through the Docker Hub.
+We can now publish it to the Docker Hub!
 
-We won't do it since we don't want to force everyone to create a Docker Hub account (although it's free, yay!) but the steps would be:
+*Note: you don't have to do the exercises in this section,
+because they require an account on the Docker Hub, and we
+don't want to force anyone to create one.*
 
-* have an account on the Docker Hub
+*Note, however, that creating an account on the Docker Hub
+is free (and doesn't require a credit card), and hosting
+public images is free as well.*
 
-* tag our image accordingly (i.e. `username/imagename`)
+---
 
-* `docker push username/imagename`
+## Logging into our Docker Hub account
 
-Anybody can now `docker run username/imagename` from any Docker host.
+* This can be done from the Docker CLI:
+  ```bash
+  docker login
+  ```
 
-Images can be set to be private as well.
+.warning[When running Docker4Mac, Docker4Windows, or
+Docker on a Linux workstation, it can (and will when
+possible) integrate with your system's keyring to
+store your credentials securely. However, on most Linux
+servers, it will store your credentials in `~/.docker/config`.]
+
+---
+
+## Image tags and registry addresses
+
+* Docker images tags are like Git tags and branches.
+
+* They are like *bookmarks* pointing at a specific image ID.
+
+* Tagging an image doesn't *rename* an image: it adds another tag.
+
+* When pushing an image to a registry, the registry address is in the tag.
+
+  Eample: `registry.example.net:5000/image`
+
+* What about Docker Hub images?
+
+--
+
+* `jpetazzo/clock` is, in fact, `index.docker.io/jpetazzo/clock`
+
+* `ubuntu` is, in fact, `library/ubuntu`, i.e. `index.docker.io/library/ubuntu`
+
+---
+
+## Tagging an image to push it on the Hub
+
+* Let's tag our `figlet` image (or any other to our liking):
+  ```bash
+  docker tag figlet jpetazzo/figlet
+  ```
+
+* And push it to the Hub:
+  ```bash
+  docker push jpetazzo/figlet
+  ```
+
+* That's it!
+
+--
+
+* Anybody can now `docker run jpetazzo/figlet` anywhere.
 
 ---